Explain the types of Plastids in brief.
• Explain the functions and structure of Golgi bodies.
• What is a nucleoid?
• What are the differences between plant cell and animal cell?
• What is the function of chromosomes?
• Why are Plant cells more rigid than animal cells?
• Explain the process of osmosis in detail.
• Draw labelled diagrams of plant cell and animal cell.
• What would happen if an animal cell is kept in distilled water for 24 hours?
• How is mitochondria and chloroplast similar to each other?
• Why are lysosomes called
a. Natural scavengers of the cell?
b. Suicidal bags of the cells?
• Cells of ants and elephants are same in size. Do you agree with this? Give reason.
Answers
•Types of plastids -
Chromoplast: they contain the yellow, orange or red coloured pigment and their function is to attract insects for polination
Leukoplast: they contain a colourless pigment and store starch
Chloroplast: they contain the green coloured pigment called chlorophyll which help in photosynthesis
•Golgi body structure is formed with vesicle like sacs called cisternae and the Golgi body function is to process proteins and sort cellular proteins for delivery inside or outside the cell.
•A plant cell contains a large, singular vacuole that is used for storage and maintaining the shape of the cell.Animal cells have many, smaller vacuoles. Plant cells have a cell wall, as well as a cell membrane whereas animal cell has only cell membrane.Animal cells have lysosomes, that contain digestive enzymes to break down cellular macromolecules. Plant cells rarely contain lysosomes as the plant vacuole and the Golgi bodies handle molecule degradation of waste cellular products.
•Chromosomes are composed of chromatin fibres which contain the genes which control the heridatary features of the cell.
•Plant cells are more rigid than animal cells as they have cell wall, which give rigidity and shape to the cell.
•Osmosis is a process which occurs when there is a difference in solute concentration between two solutions separated by a semipermeable membrane. A semipermeable membrane allows passage of water but not of solutes. The passage of water occurs because of a pressure difference of water between the two solutions. The pressure needed to to stop the flow of water from a solution with low osmolarity to a solution with higher osmolarity is in fact called osmotic pressure, and is calculated with the van’t Hoff equation. The concentration of osmotically active particles in a solution is called osmolarity. When two solutions have the same osmolarity they are called isosmotic, otherwise one is defined hyposmotic and the other hyperosmotic.